Voucher Not Posted During Voucher Post - Withholding Calculation Error

A voucher did not post during the Voucher Post AP_PSTVCHR process.  The following message was received:  An error has occurred during the Withholding Calculation process: BU: XXXXX, Voucher: XXXXXXXX, Could NOT find Vendor setup for XXXXX(SETID).

I checked the Procurement Control > Withholding page for the Business Unit.  The effective date was later than the effective date on the vendor.   I updated the date to be prior to the vendor location / address effective date and reran but the voucher still did not post. The dates on the withholding entity and withholding rule were fine - they were earlier than the new effective date on the procurement control.